Background: The aim of the study was to introduce a new test to detect small areas of suppression in the binocular visual field and to lower the minimum age at which a suppression test could be identified correctly. Two tests were compared: the Binocular Polaroid Test (poltest), introduced in clinical practice a few years ago and used in screening programs for vision impairment; and the Second Generation Binocular Polaroid Test (polstar), more recently designed to have simpler answers than the poltest.
Methods: One hundred and eighty-two children were examined consecutively. To assess the validity of the two tests, sensitivity, specificity, predictive value, and phi coefficient were calculated. The applicability of the two tests and the speed of the responses was assessed by means of the test of probability of binomial distribution.
Results: The polstar has appeared to be simpler and easier in younger patients (age range 20 to 36 months, P = 0.078), and has shown 100% of specificity with a sensitivity of 84% for the polstar 1 and of 100% for the polstar 2.
Conclusion: The results appear to demonstrate that the poltest has been improved, and that the polstar may be considered an interesting investigation device for early detection of monocular visual impairment.